Most U.S. airlines did a better job in key performance metrics like on-time arrivals and lost or mishandled baggage in the first half of the year, according to the Department of Transportation’s most recent Air Travel Consumer Report. Unfortunately for the airlines, June’s monthly statistics — particularly consumer complaints — are moving in the wrong direction.

The good news: For the first half of 2012, the nation’s airlines posted their best average on-time and baggage-handling performance since DOT started keeping score 18 years ago. Between January and June, 83.7% of all flights arrived within 15 minutes of schedule. The airlines also lost or mishandled fewer than three bags for every 1,000 passengers during the first half of the year.

The bad news: DOT’s monthly report on the 15 largest U.S. airlines found, on average, only 80.7% of all flights arrived on time in June — that’s 2.7% worse than May’s performance. The airlines also averaged 3.35 lost or mishandled bags per 1,000 passengers, compared to a rate of 2.8 per 1,000 passengers in May. The number of complaints also rose in June to 1,353 from May’s 1,260 — and even last’s month’s numbers were nearly double the number of complaints the agency received in June 2011.

Stats like these make it easy to see why consumers hate airlines. Four airlines made the American Consumer Satisfaction Index’s most recent “15 Most Disliked Companies in America” list. United Continental (NYSE:UAL) ranked fifth on a list dominated by outage-prone utilities and pay-TV companies; American Airlines (PINK:AAMRQ), US Airways (NYSE:LCC) and Delta Air Lines (NYSE:DAL) took spots seven through 10, respectively.

Although average performance can highlight the broad direction the airline sector is moving, it reveals little about how well individual airlines are meeting — or missing — expectations. Here are June 2012’s best and worst airlines as measured by performance in three areas: on-time flights, mishandled baggage and complaints: